You should be able to take out the tube from the firewall. Just hold the grey piece up against the firewall with one hand and pull on the hose with your other hand. Mine slid off very easily. Then I capped the gray piece with rubber cap. I couldn't find one from a local autoparts store so I ordered this assortment from Amazon - Dorman 02253 Bypass Cap Assortment. Engine bay looks cleaner with out that horn looking thing attached to the TMIC.